中文摘要：

The microstructure and mechanical properties of the rheo-diecasting(RDC) A390 alloy under as-cast and T6 heat treatment conditions were investigated.The results indicate that the RDC sample has fine and uniform microstructure throughout the sample under the as-cast condition,and the average size of primary Si spheroids is 20-30 μm.Meanwhile,the intermetallic compounds in RDC sample are reduced.Compared with the alloy produced by conventional liquid die-casting(LDC),RDC samples have improved tensile strength,ductility,hardness and wear resistance.It is also found that heat-treatment of the RDC A390 alloy under T6 condition,can substantially improve mechanical properties,with the tensile elongation more than 100% improvement.